- Milk fat content for thermophilic yogurt
- Quantity of milk for thermophilic yogurt
- Quantity of culture for thermophilic yogurt
- Culturing temperature for thermophilic yogurt
- Culturing time for thermophilic yogurt
- Culturing frequency for thermophilic yogurt
- Potential contamination sources for thermophilic yogurt
- Runny thermophilic yogurt activation batch
Are you using regular pasteurized, homogenized, whole milk?
It’s important to use only regular pasteurized, homogenized milk for activation. See instructions for making raw milk thermophilic yogurt.
Non- and low-fat milk will remain quite soft and you may miss the signs that your milk has finished culturing. When using whole milk, be sure your milk is homogenized. If not, scoop out some of the fat before beginning the culturing process. It’s much easier to activate the starter in homogenized milk.
If you are outside the US, your milk may not be required to state that it is Ultra Pasteurized. Ultra Pasteurized and UHT milk are heated to such high temperatures, the heirloom cultures may not perform reliably. Call the dairy to learn more about the pasteurization temperature.
How much milk are you using?
To activate the culture, use 1 packet in 1 quart of milk. We completely understand the desire to make large batches! Heirloom yogurts do require an activation, or “wake up” period, though, Rushing may result in having to start over with a new starter.
After activation, you can make as much as 2 quarts (one half-gallon) per batch. Heirloom cultures do not do well with larger batches.
How much culture are you using?
Never use more than one packet to activate. After activation, never use more than 2-3 tablespoons of starter per quart of milk. While it is tempting to use more for a “stronger” yogurt, this is not the case. Too much starter will cause the yogurt to fail and kill the starter.
What is the temperature in the space you are culturing? Have you verified that the temperature is being maintained?
Heirloom thermophilic yogurts simply cannot tolerate temperatures higher than 112ºF.
To test the temperature in the yogurt maker, pour 112ºF water into the container and take temperature readings at various time intervals, to ensure that the container is holding the correct temperature range. For more details: http://www.culturesforhealth.com/learn/yogurt/testing-yogurt-maker/
How long are you culturing?
The initial activation batch may take up to 12 hours, but be sure to start checking periodically after 6 hours.
Once your starter is active, do not allow your starter to incubate longer than 8 hours. If your yogurt is not setting, check the temperature, and amount of starter.
If you need to culture your yogurt for longer than 8 hours, remove enough yogurt to start your next batch as soon as it sets. This will allow you to keep a nice, strong “mother culture” for you next batch while still achieving the very tangy yogurt of a long culturing time.
How long is your starter stored between batches?
Be sure to culture your yogurt at least every 7 days.
If it’s been up to 10-14 days without making a batch, try a small batch with 1 tablespoon of yogurt in 2 cup of milk. If this sets, make a second batch within 2 days to strengthen your starter.
For tips on taking a break from making yogurt: http://www.culturesforhealth.com/learn/yogurt/storing-taking-break-yogurt/
Is there anything culturing near your yogurt?
While pretty tolerant, it’s best to keep yogurt at least 4’ from other cultures. If you’re worried about contamination from another source, it’s a good idea to use a solid lid instead of the breathable cover. We love these! http://www.culturesforhealth.com/plastic-lids-wide-mouth-jars.html
Remember! It’s completely normal for an activation batch of heirloom yogurt to set unevenly, or even look no different from warm milk.
These are not like the commercial, direct-set starters, and take some time to wake up. Do not discard your activation batch!